US Patent Application Publication No. 2006-0122159 discusses pharmaceutical formulations useful for treating infections in animals, particularly otic infections. The compositions are generally described as comprising a corticosteroid, antibiotic, and triazole. They include, for example, suspensions comprising mometasone furoate monohydrate, orbifloxacin, and posaconazole. A specific formulation illustrated in US Patent Application Publication No. 2006-0122159 is shown in Table 1:
TABLE 1Formulation from Example 1 in US Patent Appl. Publ. No. 2006-0122159Ingredientmg/gMicronized Orbifloxacin10.0Micronized Mometasone Furoate Monohydrate1.0Micronized Posaconazole1.0Mineral Oil USP (40 centistokes)685.0Plasticized Hydrocarbon Gel - Ointment Base quantity sufficient (PLASTIBASE ® 50W, which is 5% to bring the total polyethylene and 95% mineral oil)mass to 1 g
Applicants have observed an increase in at least one mometasone degradation product over time when the above formulation is stored at room temperature. Applicants have further observed that the orbifloxacin in the formulation accelerates the formation of the degradation product. The formation of the degradation product generally can be minimized by storing the formulation at colder temperatures (e.g., 5° C.). There is, however, a need for a formulation that can remain stable at greater temperatures (e.g., room temperature). This invention provides such a formulation.